It turned Lauren Conrad and her rich kid co. into stars, but during its six-season run but The Hills also featured a bunch of already established celebs!

Yep, the MTV series featured all of Tinseltown’s hottest from Hilary Duff to Lady Gaga and almost every A-lister in between – including the now queen of reality TV Kim Kardashian – hanging out at all the hottest parties in Hollywood.

Um, they must have misplaced our invite…

So in honour of the reality show’s 10th anniversary – which we all have to admit we binge watched in our PJ’s more than once – let’s check out the celebs who made the coolest cameos in The Hills.

Lily Collins – Season 3, Episode 19

Photo: MTV

After she was dubbed “the girl who didn’t go to Paris” in the show’s first season, Lauren traveled to the City of Lights with bestie and work pal Whitney Port for Teen Vogue feature at the Crillion Ball – and who was one of the debutantes?

Well none other than Love, Rosie actress Lily Collins of course. How convenient!